Alloy



Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE l'lal No. 243,873. 1937 In Great Britain December 10,

4 Claims. (Cl. 75 128) This invention primarily relates to resistance wire tor electric fires, heaters and the like and has ior its object to provide an alloy having a very high resistance to oxidation at high temperature and to attack by acids, sulphur and other corrosive agents. The alloy is suitable, among other purposes, for use in the manufacture of electric resistance wires and other articles which have to be exposed to the action oi. the atmosphere at high temperatures.

' More particularly the invention relates to nickel chromium alloys containing to 30% chromium with the balance nickel and to nickel-chromiumiron alloys containing 10430 parts chromium, and

the balance nickel, up to 50% of which is replaced by iron, by iron and tungsten (the percentage of the latter in the composition being up to 10), by iron and molybdenum (the percentage of the latter being up to 10), by iron and cobalt (the percentage of the latter being up to 10) or by iron and manganese, zirconium, aluminium or uranium (the percentage of manganese, zirconium, aluminium or uranium in the composttion being up to 2).

95 In accordance with my invention, during the manuiacture of an alloy such as above indicated, there is added to the molten charge with or without additions of rare earth metals such as cerium from .01% to 2%, or alkaline earth metals, such as calcium from .01 to .5%. 35 From .01% to 0.50% Mg may be added for deoxidising purposes.

The combined use of thorium and silicon gives much improved results as compared with the use of thorium only, and the use of this combination 40 of thorium and silicon together with either a rare earth, or an alkaline earth metal gives an outstanding improvement in results.

The following examples will show the eflect oi the various additions. The hours figure gives the 45 life oi a specimenwire oi .025" diameter when tested by the Bash and Harsch method with a starting temperature of 1175 0., all tests being carried out under uniform conditions. Basis metal 80% nickel, 20% chromium.

Example 1 Hours Addition of Th 38 Example 2 Additions of .25% Th, 1% Si 128 Example 3 Additions of .25% Th, 1% Si, .15% Ca 242 Example 4 Additions of 25% Th, 1% s1, 15% Ca,

.25% Zr I 244 Example 5 Additions of 25% Th, 1% Si, .15% Ca, .5% U- 263 Example 6 Additions of 0.125% Th, 1% Si, .125% Ce,

What I claim is:

1. A heat resisting alloy consisting essentially of 10 to chromium, .01 to 2% thorium, .25 to- 3% silicon, .01 to 2% cerium, the balance consisting of iron group metals.

2. A heat resisting alloy consisting essentially of 10 to 30% chromium, substantially .125% thorium, substantially 1% silicon, substantially .125% cerium, the balance consisting of iron group metals.

3. A heat resisting alloy consisting essentially of substantially 20% chromium, .01 to 2% thorium, .25 to 3% silicon, .01 to 2% cerium, balance nickel.

4. A heat resisting alloy consisting essentially of substantially 20% chromium, substantially .125% thorium, substantially 1% silicon, substantially .l25% cerium, balance nickel.

WILLIAM MARRIOTT KAY. 

